Telephone exchange system



3 I c. B. FOWLER 1,834,393

TELEPHONE EXCHANGE SYSTEM Filed Feb. 12, 1950 /Nl EN7'O/? C. B. FOWLERIts objects are to effect economy inthe use.

i the subscriber against falsecharges andrto' otherwise improvethQOPQIltlOll oftelephone Patented Dec. 1, 1931 UNITED STATES m@E-mjomci v CLARENCE B. FOWLER, or UE NS VILLAG -NEW YoRK, AssIGNo 'TO- BELLrELE V PHONE LABORATORIES, INCORPORATED, F NEW Y RK, N ."Y.,V ACORPORATION OF NEW YORK TELEPHONE EXCHANGE s sirEM Application filedFebruary 12,1930. Serial No; 427,675;

in which the service charge is based on the duration of conversation.

of the central olfice equipment, to. safeguard systems.

1) Service charging systems have been sug-;

gested in which a source of meter operating current, wlnch isperiodically reversed by a timing device, is connected at the centraloffice to the subscribers. llne during the con versational period tocause successivejactuations of the meter; In order to safeguard.

the subscriber against false operation of his meter due to momentaryopenings of the line, it has been proposed to introduce a tune delayafter the called subscriber answers and before the meteribegins tooperate. delay is effected by means of interrupter driven contactsindividual to thecord cir cuits.

According to my invention a considerableeconomy is effected andanimprovement' is secured over these prior systems by means of a timedelay mechanism which is common, to a large number of cords orconnecting circuits.

Thisinvention has been shown in the ac,' companying drawing in which ithas been incorporated in a cord circuit well known in the art.: Acalling subscribers line and a called subscribers line have alsobeenshown in diagrammatic form and equipped with service meters. 1 f V Thedescription of a connection by means of this cord circuitfrom acallingsubscriber to a called subscriber will nowfibe made.

When the operator inserts plug 2 of cord circuit A into jack 8 ofacalling subscribers llne 4, in response to an lncoming call, a C11- cuitfor lighting lamp 1O is-clos'ed and the lower left-hand Winding ofrepeating coil 7 windingof relay. 5, over the subscribers loop,

throughthe plug 2'and jack 3, upper left- This hand of repeating coil 7,leftehand armature and baclrcontact of relay 6 to ground, Theoperationof relay 5 closes an obvious shunt circuit for the supervisory lamp 10,to battery through a common interrupter 11. This; circuit is alternatelyclosed and opened by the'interrupter to cause lamp-1O to beintermittently lighted and extinguished. The operator in response tothis signal actuates the talkinglrey. 12 for the connection. ofhertelephone set. across the tip and ring conductors of thefcord tojascertainthe number of the desired subscriber.. The operation of key 12also causes the operat on of relay 13 over-an obvious circuit throughthe left-hand winding of this relay. Relay 13 provides a locki-ngcircuitfor itself through its righthand Winding under control of thesupervisory relay 5 and disconnects the interrupter from the lamp 1Owhich-is extinguished due .to the shunt path to battery established atthe inner left hand armature and-front contact of relay'18.

When the operator receives the number of the wanted subscriber she imaycomplete the connection to this subscribers line 15 loyinserting plug 16into jack 17. Thesupervisory lamp 18 is thereby lighted over the sleevecircuit established through plug 16, and jack 1']. The desiredsubscriber may 'now be rung in the; usual manner through the operationof a ringing key not shown andwhen this subscriber answersthe callthesupervisory relay 2-0 is operated through the vsubsc'rilrxers loopin theusual manner. Relay 20 in operating establishes a shunt circuit for lamp18, which is thereby extinguished and also closes: a circuit for theoperation of relay 21 from battery, armature and front contactofrelay,20, left hand armature and back contact of relay Winding of relay 2l,resistance 23, sleeve terminals of plug 16 and jack 17 to ground. it Qr, l Relay 21 in operating established a connection from ground at theouter contacts: of the left armature of relay 6, left-hand armature andfront contactof relay 21 to one side of relay 24. Relay 2 4: will nowoperateas soon as thecircuit through its make-before-break contactsiscompleted tobattery over a com.- t-

interrupter is connected to the circuit of relay 6 two seconds after theconnection from the live segment of the interrupter 25 is opened. Theconnection to battery through interrupter 26 causes relay'6 to operateover its right-hand winding as the ground connection for the other s1deof this winding 1s completed at the right-hand armature and fronteontact of relay 21. Relay 6 provides a lacking circuit for itself undercontrol of relay 21 independent of the interrupter 26 from batterythrough its outer right-hand armature and front contact. Relay 6 alsoopens the circuit for relay 24: so that it releases after re-- lay 6 isoperated, but relay 24k is made slow to release so as not to open thecircuit from interrupter 26 too soon or before relay 6 has closed itslocking circuit.

In case now, for example, relays 20 and 21 had been operated momentarilyand released between the operation of relay 2 1 and the closure of theconnection through interrupter 26 for the operation of relay 6, relay 2%would have released and consequently the operation of relay 6 duringthis cycle of interruptions by the interrupters 25 and 26 would havebeen prevented. Such a momentary operation of relays 20 and 21 may becaused by the called party momentarily operating his switchhook or bythe cord being connected to a so-called busy-back circuit or for anyother reason. False operations of relay 6 are thus prevented under thesecircumstances, without interference with the eventual operation of relay6 when conditions are normal. The operation of relay 6 opens the circuitfor relay 24: and disconnects the normal talking battery from the tipand ring conductors of the cord and connects these conductors to themeter operating and talking battery 29. The polarity of this battery isreversed at periodic intervals under control of interrupter 30 and relay31 and will, as is wellknown in the art, cause the periodic operation ofthe meter 32 of the calling subscribers line. It should be noted thatduring the interval between break and make of the contacts on relay 6 tosubstitute batteries a connection to battery and ground throughresistance 33 is maintained by relay 2a which is made slow to releasefor this purpose. In this manner a gradual change in the battery supplyis caused and excessive click in the calling subscribers receiver isthereby prevented.

lNhen the called partly disconnects,supervisory relay 20 is releasedcausing the release of relay 21 which in turn causes the release ofrelay 6 if the called party has already replaced his receiver on theswitchhook. 111 case, however, that the calling party still has hisreceiver oil the hook, relay 6 will be held operated through itsleft-hand winding as long as timing battery is connected through thiswinding by the operation of relay 81. The circuit in this case willextend from battery, upper, armature and front contact of relay 31,inner left-hand contacts, winding of relay 6, outer left hand armatureand front contact of relay 18 to ground through the sleeve terminals orplug 2 and jack 3. When relay 31 releases and this connection is changedto ground, relay 6 will release. *y insuring the release of relay 6 atthis interval, a click in the calling subscribers receiver is preventedand any operation of relay 21 by the called subscriber momentarilyoperating his switchhook cannot cause a false operation of the servicemeter l i hen the. calling party hangs up his receiver, relays 5 and 13are released, thus removing tne shunt for lamp 10 which is now lightedthrough the sleeve circuit. In case the'calling party should recall byoperating his switchhook, relay 5 would be reoperated and-cause thesupervisory lamp 10 to be alternately lighted and extinguished. T he oerator would then answer this ca l by the operation of the talking key12 and cause relay 13 to operate to again shunt the lamp 10previouslydescribed.

Tn case'the desired subscribers line is a free call line, the operatoroperates the nocharge key 3 1. The operation of this key causes theoperation of relay 22 which looks under control of the sleeve circuit,the resistanceof this winding replacing the resistance 35 in the sleevecircuit. The operation of relay 22 ope s at the left-hand armature andback contact the circuit for relay 21, and thus prevents its operationwhen the called subscribed answers. As relay 21 is not operated, relay 6cannot operate and the no anal talking current supply cannot thereforebe changed to the timing battery sup ply and no charge made on the meter32 for this connection.

it should be understood that while the in vention has been onlyillustrated in connection with one type of circuit it may readily beapplied to other circuits without departure from the spirit thereof.

W hat is claimed is:

1. in a telephone system, calling lines and called lines, meters forsaid calling lines, a plurality of connecting circuits forinterconnecting calling lines and called lines for conversation, asource of current for supplying the calling lines, means controlled by acalled partyfor connecting said source to a calling line, means forchangingthe flow of current from said source to cause the operation of acalling subscribers meter, and contactmeans common to said connectingcircuits for in-- troducing a delay between the time the calledsubscriber answers and the time when the meter operating means'isconnected to the calling line.

2. In a telephone system, calling lines, called lines, meters for saidlines, connecting circuits for interconnecting calling lineswith calledlines, means controlled by a called party for operating the meter or acalling party, and meanscommon to a plurality of connecting circuits forintroducing a delay between the time the called party answers the calland the meter operatingmeans becomes eitective.

8. In a telephone system, calling lines, called lines, meters for saidlines, a plurality of connecting circuits for connecting calling lineswith called lines, means controlled by a called party for operating themeter of the calling party, and a series of interrupte-rs common to aplurality of connecting circuits for introducing a delay in the controlby the called party of the meter operating means until a certain periodhas elapsed after the called party has answered the call.

4. In a telephone system, calling lines, called lines, meters for saidlines, a plurality of connecting circuits for connecting calling lineswith called lines, means for operating the meter of the called line whena connect-ion tain interval'after the operation of said third vmentioned relay.

7 In a telephone system, calling lines,

called lines, meters for said lines, connecting circuits forinterconnecting calling lines with called lines, means for operating themeter of a callingline when a connection is established, a relayresponsive to the establishing of a connection, a second relay forcontrolling the meter operating means, a third relay, means foroperating said third mentioned relay in response to the operation ofsaid first mentioned relay, means responsiveto the operation of saidthird mentioned relay for operating said second mentioned .relay acertain interval after the operation of'said third mentioned relay, andmeans for maintaining said'second mentioned relay operated under controlof said first mentioned relay.

In witness whereof, I hereunto subscribe my name this 10th day ofFebruary, .1930. CLARENCE B. FOWLER.

is established, a relay responsive to the estab lishing of a connection,a second relay for controlling the meter operating means, and

means responsive to the operation of the first relay for actuating thesecond relay when a predetermined period of time has elapsed after theactuation of the first relay;

5. In a telephone system, calling lines,

called lines, meters for said lines, a plurality of connecting circuitsfor connecting calling lines with called lines, means for operating themeter of a calling line when a connection is established, a relayresponsive to the establishing of a connection, a second relay forcontrolling the meter operating means, interrupters common to aplurality of connecting circuits, and means controlled by saidinterrupters and the first relay for actuating the second relay when apredetermined period of time has elapsed after the operation of saidfirst relay if said relay has been maintained continuously operatedduring this period. 6. In a telephone system, calling lines, calledlines, meters for said lines, connecting circuits for interconnectingcalling lines with called lines, meansfor operating the meter of acalling line when a connection is established, a relay responsive to theestablishing of a connection, a second relay for controlling the meteroperating means, a third relay, means for operating said third mentionedrelay in response to the operation of the first

